Pineal neoplasms frequently cause obstructive hydrocephalus and require histopathological diagnosis to decide the treatment regimen. They might be treated by surgical resection or chemoradiotherapy according to the pathological diagnosis. As a minimally invasive initial treatment, an endoscopic approach from Kocher’s point enables both third ventriculostomy and biopsy.
Pineal neoplasms have a significant impact on children although they are relatively uncommon. They account for approximately 3-11% of all childhood brain tumors, which is considerably higher than the <1% seen in adult brain tumors. These tumors can be divided into three main categories: germ cell tumors, parenchymal pineal tumors, and tumors arising from related anatomical structures. Obtaining an accurate and minimally invasive tissue diagnosis is crucial for selecting the most appropriate treatment regimen for patients with pineal gland tumors. This is due to the diverse treatment options available and the potential risks associated with complete resection. In cases where patients present with acute obstructive hydrocephalus caused by a pineal gland tumor, immediate treatment of the hydrocephalus is necessary. The urgency stems from the potential complications of hydrocephalus, including increased intracranial pressure and neurological deficits. To address these challenges, a minimally invasive endoscopic approach provides a valuable opportunity. This technique allows clinicians to promptly relieve hydrocephalus and obtain a histological diagnosis simultaneously. This dual benefit enables a more comprehensive understanding of the tumor and assists in determining the most effective treatment strategy for the patient.
The pineal gland is a neuroendocrine gland located in the epithalamus that is responsible for regulating biological rhythms in vertebrates. Its anatomical boundaries include the posterior surface of the wall of the third ventricle, which forms the base of the gland, the splenium of the corpus callosum superiorly, and the thalamus surrounding both sides. It has a pinecone shape and extends posteriorly and inferiorly in the quadrigeminal cistern1,2.
Pineal neoplasms are relatively rare tumors and are predominantly childhood malignancies, accounting for 3-11% of all childhood brain tumors compared with <1% of adult brain tumors1,3,4. Age, sex, and ethnicity can modify the relative incidence of pineal neoplasms5. Pineal tumors are classified into three types: germ cell tumors, pineal parenchymal tumors, and tumors arising from neighboring anatomical regions. Germinomas are the most frequent pineal tumors, accounting for up to 50% of pineal tumors in Europe1,3.
Tumors of the pineal gland are pathologically diverse and their optimal management remains controversial6. Advances in neuroendoscopy have significantly contributed to treating pineal region tumors. Neuroendoscopic techniques are minimally invasive, effective, and safe in treating these tumors. With this technique, it is possible to treat hydrocephalus and obtain a biopsy simultaneously7. In most cases, simultaneous endoscopic third ventriculostomy (ETV) and tumor biopsy is the first-choice surgical procedure for pineal region tumors due to the effectiveness of radiotherapy and chemotherapy in most histopathological subtypes. Various techniques for simultaneous ETV and biopsy have been described, and there is currently no standard technique for performing this procedure8.
The Institutional Review Committee of the Istanbul Faculty of Medicine approved the study protocol. Before the start of the study, the patient was asked to sign an informed consent form outlining the purpose of use and publication of their data.
1. Preoperative procedures
2. Surgical technique (Figure 2)
3. Postoperative procedures
Preoperative magnetic resonance imaging (MRI) revealed a pineal tumor and triventricular hydrocephalus. Before the surgery, we ensured that our endoscope set, 4F Fogarty balloon catheter (see Figure 1), and all required materials (see Table 1) were checked. The size of the pineal tumor was initially measured at 30 mm x 15 mm x 20 mm. However, on postoperative MRI scans, it was observed that the tumor had increased in size to 35 mm x 52 mm x 45 mm, suggesting a progressive nature of the tumor. Fortunately, after undergoing chemotherapy, there was a positive response to treatment. The tumor size was significantly reduced to 15 mm x 15 mm x 10 mm, indicating a successful outcome.
Additionally, the contrast uptake was also significantly reduced, further supporting the effectiveness of the chemotherapy treatment. Figure 3 provides a visual representation of the reduction in tumor size and hydrocephalus throughout the treatment period. This graphical representation highlights the positive progress made in managing both the tumor and hydrocephalus. During the surgical procedure, continuous irrigation was employed, making it difficult to accurately measure the amount of blood loss. However, it is worth noting that no intraoperative transfusion was required for this patient, indicating that the blood loss was not significant.
Furthermore, there was no significant decrease in hemoglobin levels after the surgery, suggesting that the patient's blood levels remained stable throughout the procedure. Overall, the combination of chemotherapy and surgical intervention has proven to be effective in reducing the size of the pineal tumor and managing the triventricular hydrocephalus. The positive response to treatment is evident in the reduction of tumor size and contrast uptake, providing hope for the patient's recovery.
Figure 1: Karl-Storz endoscope set and 4F Fogarty balloon catheter. 1: Biopsy Forceps; 2: Endoscope sheath; 3: Obturator; 4: Ventriculoscope; 5: Bipolar coagulation electrode; 6: 4F Balloon catheter. Please click here to view a larger version of this figure.
Figure 2: A schematic illustration of endoscopic third ventriculostomy and pineal biopsy with a rigid endoscope, utilizing Kocher's point. Please click here to view a larger version of this figure.
Figure 3: A magnetic resonance imaging scan performed on a patient with a pineal gland tumor and triventricular hydrocephalus. (A) Preoperative contrast-enhanced T1 sequence sagittal; (B) preoperative contrast-enhanced T1 sequence axial; (C) preoperative T2 sequence sagittal; (D) preoperative T2 sequence axial. (E) Contrast-enhanced T1-sequence sagittal MRI before chemotherapy and 1 month after surgery; (F) contrast-enhanced T1-sequence axial MRI before chemotherapy and 1 month after surgery.(G) T2 sequence sagittal MRI before chemotherapy and 1 month after surgery; (H) T2 sequence axial MRI before chemotherapy and 1 month after surgery. (I) Contrast-enhanced T1-sequence sagittal MRI at the second month after chemotherapy; (J) Contrast-enhanced T1-sequence axial MRI at the second month after chemotherapy and axial.(K) T2 sequence sagittal MRI at the second month after chemotherapy and axial; (L) T2 sequence axial MRI at the second month after chemotherapy. Please click here to view a larger version of this figure.
The description of the ETV and biopsy for pineal tumors was first described in the 1970s. Historically, the fear of uncontrolled hemorrhage has always existed. However, owing to advances in endoscopic surgery techniques, bleeding control is not a major complication for experienced surgeons nowawadays9,10. According to several cases in the literature, endoscopic management has been found to be effective as an initial step for pineal region tumors presenting with hydrocephalus. The primary aims of endoscopic management are both CSF drainage and tissue diagnosis for further management8.
Pineal tumors are a diverse group of tumors with different histological characteristics. The tumors can be classified into four main groups: germ cell tumors, tumors of pineal origin, tumors of neuroepithelial origin, and a variety of other tumors, including metastases. Considering the wide range of treatment options available for these tumors and the potential risks associated with complete resection, it is important to diagnose the tumor accurately at the time of diagnosis using minimally invasive tissue sampling. Patients presenting with acute hydrocephalus secondary to pineal gland tumors require immediate treatment of the hydrocephalus and minimally invasive endoscopic surgery offers the opportunity to simultaneously diagnose the histology1,7.
ETV with simultaneous biopsy of a pineal gland lesion has been adopted as a management strategy for these rare tumors6,11,12,13. This approach has several advantages, including biopsy sampling in addition to CSF drainage, CSF sampling for the study of tumor markers such as alpha-fetoprotein and human chorionic gonadotropin, and the ability to minimize bleeding from the rich vascular tissue under direct visualisation7,14,15. The tumor types in this region exhibit a wide range of diversity, and within each tumor, there may be heterogeneity, such as teratoma, pineocytoma, and glioma. Therefore, to determine a formal treatment strategy, an accurate diagnosis is essential1,6,16.
The two most common intraoperative complications during endoscopic pineal region biopsy are intraventricular hemorrhage due to venous bleeding and iatrogenic contusion of the fornix due to rigid endoscope use in patients with narrow foramen Monro17. The incidence of these complications decreases significantly with increasing experience in endoscopic surgery, preoperative planning, and appropriate patient selection. When a single access site is used for ETV and pineal biopsy, the use of a ventriculoscope with a 30° angled lens provides a wider field of view and less fornix ecartation, resulting in fewer complications18.
There is no consensus on the optimal approach to performing ETV before tumor biopsy in a single-port procedure. The rationale for choosing ventriculostomy as the first step is that the potential for visual blurring may complicate ETV due to the risk of tumor hemorrhage after biopsy. In patients with critically high intracranial pressure and obstructive hydrocephalus, treatment of hydrocephalus should be prioritized17.
Various techniques such as ETV and ventriculoperitoneal shunt placement have been used in the treatment of obstructive hydrocephalus associated with pineal region tumors19. Many patients may not need CSF diversion after the lesion is removed or reduced in size with chemotherapy and radiotherapy20. For obstructive hydrocephalus associated with lesions in the pineal region, ETV is a widely used minimally invasive technique. Furthermore, tumor biopsies obtained with ETV, especially those used to diagnose germ cell tumors, may avoid surgical resection due to their high radiosensitivity21.
Endoscopic biopsy and third ventriculostomy can be performed with both rigid and flexible endoscopes in a single session using the monoportal technique11. However, the inferior optical quality of the flexible endoscopic system has become a significant limitation, potentially hindering the ability to detect tumor spread22. In addition, the smaller size of the flexible forceps compared to the rigid endoscope forceps may affect the size of the biopsy sample, resulting in inconsistent histology results10. Moreover, it may be difficult to maneuver the flexible ventriculoscope through the Foramen of Monro and toward the massa intermedia of the third ventricle. Furthermore, the tumor should be biopsied and coagulated without irrigation. More importantly, a lot of bleeding from the biopsy site could lead to total loss of vision10,11.
In conclusion, treatment regimens for these tumors vary. Complete resection carries a high risk of morbidity and mortality due to its close location to important anatomical structures. In cases where patients present with acute obstructive hydrocephalus caused by a pineal gland tumor, it is imperative to treat the hydrocephalus promptly. The endoscopic approach provides the possibility of simultaneous histological diagnosis23.
The authors have nothing to disclose.
This study did not receive any funding.
Adson periosteal elevator | Ruggles-Redmond | RO263 | Semi-sharp, 5 mm, curved 6-3/8, length 164 mm |
Automatic skin retractors | Integra | 3,72,245 | Heiss Automatic Skin Retractor Length – Overall (mm): 102 Length 1 – Tip/Jaw (mm): 8 |
Balloon catheter | Edwards Fogarty | 120804FP | Length (cm): 80, Catheter size (F): 4, Inflated balloon diameter (mm): 9 |
Biopsy Forceps | Karl Storz LOTTA CLICKLINE Grasping Forceps | 28164 LE | Rotating, dismantling, single action jaws, diameter 2.7 mm, working length 30 cm |
Bipolar coagulation electrode | Karl Storz LOTTA | 28161 SF | Diameter 1.3 mm, working length 30 cm |
Bisture | Beybi | 24,02,502 | Beybi Bisture Tip. No: 20 and No: 11 |
High-speed drill | Medtronic Midas Rex MR8 | MR8™ Electric Plus EM850 | Perforator tip used |
Obturator | Karl Storz LOTTA | 28164 LLO | Use with Operating Sheaths for ventricular puncture |
Operating sheath | Karl Storz LOTTA | 28164 LSB | Graduated, rotating, outer diameter 6.8 mm, working length 13 cm |
Ventriculoscope | Karl Storz LOTTA Ventriculoscope with HOPKINS | 28164 LAB | Wide angle telescope 30°, angled eyepiece, outer diameter 6.1 mm, length 18 cm, working channel diameter 2.9 mm, irrigation/suction channel diameter 1.6 mm |